Furnace terminal connection


  #1  
Old 04-22-17, 10:26 AM
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Furnace terminal connection

I'm connecting smart thermostat, and was missing the common wire. So I ran a new cable to to the furnace, however I don't have the normal terminals and wondering if it's possible for me to hookup the common wire anywhere on the unit.

https://i.imgur.com/BlPL8fK.jpg
https://i.imgur.com/2Kf7thp.jpg
https://i.imgur.com/SCduf1R.jpg


Unit diagram picture
https://i.imgur.com/ye5WQLK.jpg

Thank you
 
  #2  
Old 04-22-17, 10:48 AM
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Welcome to the forums.

If you have A/C...... the top two wires will be connected to the outside compressor.

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Old 04-23-17, 07:13 PM
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I honestly think that's a misprint on the diagram. The BL is the common, but there would be no reason for the BL/BK to go out to the condenser because all it will do is get nutted together with the BL there anyway. It's the common side of the fan relay (circuit completed by a G call). Condensers only require two leads, Y and C (unless they are multistage or heat pumps, which is not the case here).
 
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Old 04-23-17, 07:24 PM
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Yeah.... that is strange. I never traced it all the way back until you mentioned it.

So in this case it would strictly be the Blue C line and the Y to the outdoor condensor.
 
  #5  
Old 04-23-17, 07:43 PM
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If not a misprint then at least confusing. Look at the ladder diagram and note 5. BL and BL/BK are to be wire nutted together in the field, not factory.
 
 

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